Wiring Issue (Brake and rear flasher)

[Airmapper]

I did do a forum search, and I swear I read a thread on my exact issue but I can't find it now.

Anyway, I don't want to put in a full harness yet, but I do eventually. In the meantime however I need my brake lights, but am not sure where to start digging to find what exactly is wrong with them. I'm a bit lost when it comes to wiring, but I have a multimeter and can usually figure out how to use it. (I did blow one up one time, if that gives you an indication of my electrical skills....%) )

Everything seems to work, not perfectly but works, with the exception of the brake lights, and rear flashers. Turn signals and running lights do work in the rear.

My brake actuator switch is on the master cylinder, it's the manual pressure switch that has 2 pins on top and I did a continuity test with the multi meter on it and it does work (as it should, it's brand new.) To my knowledge there is no actuator on the pedal, I could not find one and think they used those starting in 67.

A wire to the rear running along the drivers side of the frame seems to be fine, but it is the only wire I see running back there. I'm assuming my issue is closer to the front?

Any help with how to diagnose this will be appreciated.

 

[Viperwolf1]

Lack of brake lights and rear flashers tells me the problem is in the rear harness or bulbs. Do the rear turn signals work?

The rear harness has a connector in the engine bay near the steering column. It's a square 4-pin connector with yellow, green, brown and orange wires. Unplug it and test for voltage on the yellow (left turn/brake) and green (right turn/brake) wires.

 

[Airmapper]

Thanks viperwolf,

Rear turn signals and running lights (rear lights dimly lit) do work, so I'm pretty confident it is not the bulb, also all of this is consistent with both driver and passenger sides. I've had the bulbs out and did not see any broken filaments, not to say that is a sure fire sign.

I will check that connector soon as I can and see what it looks like, and check it with the tester. Thanks for the diagram.

 

[BoltBuster]

By chance your not using LEDs? Whole different problem can occur with a stock flasher.

 

[Airmapper]

Well I got my brake lights working. Found a connection in the rear under the drivers side, that at some point I think my Dad had fixed, and it had rusted. I stripped off a little more wire, put it back together, and taped it back up. Good enough until I can put in a new harness.

Now I got more issues. The rear passenger turn signal stops when the brake lights are on, and my hazard lights still don't work in the rear.

 

[Viperwolf1]

Now I got more issues. The rear passenger turn signal stops when the brake lights are on, and my hazard lights still don't work in the rear.

Look at the turn signal switch for the first problem and the hazard switch wiring for the second problem. Make sure the hazard switch is connected and the flasher has power.

 

[Airmapper]

Look at the turn signal switch for the first problem and the hazard switch wiring for the second problem. Make sure the hazard switch is connected and the flasher has power.

Thanks once again. I'll study over that diagram, maybe next weekend I can get a little more done. I must be doing something right, my multimeter still works and doesn't smell weird.

 

[mortimersnerd]

I'd recommend the full harness. I just finished up a Centech install and was really surprised at the difference it made. My wiring was a mess when I got the truck, but the headlights were brighter and everything worked really well. Didn't take all that long, either. Seems like cheap insurance and a easy way to have much better reliability.

 

[Steve83]

The rear passenger turn signal stops when the brake lights are on...

Smells like a bad ground at the RHR.

...my hazard lights still don't work in the rear.

That could also be a bad ground or 2.